Primary and Secondary Cell Group Configuration

1. A method comprising: a) transmitting, by a base station, at least one control message to a wireless device in a plurality of wireless devices, said at least one control message: i) configured to cause in said wireless device: (1) configuration of a plurality of cells comprising at least one secondary cell; and (2) assignment of each of said at least one secondary cell to a cell group in a plurality of cell groups, said plurality of cell groups comprising: (a) a primary cell group comprising a first subset of said plurality of cells, said first subset comprising a primary cell, uplink transmissions by said wireless device in said primary cell group employing a first synchronization signal transmitted on said primary cell; and (b) at least one secondary cell group, a first secondary cell group in said at least one secondary cell group comprising a second subset of said at least one secondary cell, uplink transmissions in said secondary cell group employing a second synchronization signal on an activated secondary cell in said first secondary cell group as a secondary timing reference; and ii) comprising a plurality of dedicated parameters specific to said wireless device, said plurality of dedicated parameters comprising a sequence of at least one first information element, each of said at least one first information element comprising: a first cell group index of a first secondary cell group and a first time alignment timer for said first secondary cell group, wherein for each of said at least one secondary cell: (1) if said plurality of dedicated parameters comprise a cell group index for said secondary cell, assigning said secondary cell to one of said at least one secondary cell group identified by said cell group index; and (2) otherwise, assigning said secondary cell to said primary cell group; b) receiving, by said base station, a random access preamble on random access resources of a secondary cell in said secondary cell group; and c) transmitting a random access response comprising a timing advance command for said secondary cell group.

2. The method of claim 1 , wherein said primary cell group is identified by an index equal to zero.

3. The method of claim 1 , further comprising transmitting, by said base station, a timing advance command to said wireless device, said timing advance command configured to cause substantial alignment of reception timing of uplink signals in frames and subframes of a cell group at said base station, said timing advance command comprising an index identifying said cell group.

4. The method of claim 1 , wherein said at least one control message comprises at least one cell-add-modify information element, each of said at least one cell-add-modify information element comprises a first plurality of dedicated parameters in said plurality of dedicated parameters, said first plurality of dedicated parameters comprising a first cell index for a first secondary cell in said at least one secondary cell.

5. The method of claim 1 , wherein said plurality of dedicated parameters further comprise a time alignment timer parameter for each cell group in said plurality of cell groups.

6. The method of claim 1 , wherein said plurality of dedicated parameters further comprise an activation timer for said at least one secondary cell.

7. The method of claim 1 , wherein said at least one control message configured to further cause in said wireless device configuration of a time alignment timer for each of said plurality of cell groups, said time alignment timer starting or restarting in response to said wireless device receiving a timing advance command to adjust uplink transmission timing of a commanded cell group in said plurality of cell groups.

8. The method of claim 1 , wherein transmission timing of said random access preamble being determined, at least in part, employing said second synchronization signal.

9. The method of claim 8 , further comprising transmitting, by said base station, at least one timing advance command to said wireless device, said timing advance command comprising: a) a time adjustment value; and b) an index identifying said secondary cell group; and wherein said at least one timing advance command configured to cause substantial alignment of reception timing of uplink signals in frames and subframes of said secondary cell group at said base station.

10. A base station comprising: a) one or more communication interfaces; b) one or more processors; and c) memory storing instructions that, when executed, cause said base station to: i) transmit at least one control message to a wireless device, said at least one control message: (1) configured to cause in said wireless device: (a) configuration of a plurality of cells comprising at least one secondary cell; and (b) assignment of each of said at least one secondary cell to a cell group in a plurality of cell groups, said plurality of cell groups comprising: (i) a primary cell group comprising a first subset of said plurality of cells, said first subset comprising a primary cell; and (ii) at least one secondary cell group, a first secondary cell group in said at least one secondary cell group comprising a second subset of said at least one secondary cell; and (2) comprising a plurality of dedicated parameters comprising a sequence of at least one first information element, each of said at least one first information element comprising: a first cell group index of a first secondary cell group and a first time alignment timer for said first secondary cell group, wherein for each of said at least one secondary cell: (a) if said plurality of dedicated parameters comprise a cell group index for said secondary cell, assigning said secondary cell to one of said at least one secondary cell group identified by said cell group index; and (b) otherwise, assigning said secondary cell to said primary cell group; ii) receive a random access preamble on random access resources of a secondary cell in said secondary cell group; and iii) transmit a random access response on said primary cell, said random access response comprising a timing advance command for said secondary cell group.

11. The base station of claim 10 , wherein said at least one control message comprises at least one cell-add-modify information element, each of said at least one cell-add-modify information element comprises a first plurality of dedicated parameters in said plurality of dedicated parameters, said first plurality of dedicated parameters comprising a first cell index for a first secondary cell in said at least one secondary cell.

12. The base station of claim 10 , wherein said plurality of dedicated parameters further comprise a time alignment timer parameter for each cell group in said plurality of cell groups.

13. The base station of claim 10 , wherein said plurality of wireless devices are compatible with LTE release 11 or above and support configuration of multiple cell groups.

14. The base station of claim 10 , wherein said plurality of dedicated parameters further comprise an activation timer for said at least one secondary cell.

15. A wireless device comprising: a) one or more communication interfaces; b) one or more processors; and c) memory storing instructions that, when executed, cause said wireless device to: i) receive at least one control message from a base station, said at least one control message: (1) causing in said wireless device: (a) configuration of a plurality of cells comprising at least one secondary cell; and (b) assignment of each of said at least one secondary cell to a cell group in a plurality of cell groups, said plurality of cell groups comprising: (i) a primary cell group comprising a first subset of said plurality of cells, said first subset comprising a primary cell; and (ii) at least one secondary cell group, a first secondary cell group in said at least one secondary cell group comprising a second subset of said at least one secondary cell; and (2) comprising a plurality of dedicated parameters comprising a sequence of at least one first information element, each of said at least one first information element comprising: a first cell group index of a first secondary cell group and a first time alignment timer for said first secondary cell group, wherein for each of said at least one secondary cell: (a) if said plurality of dedicated parameters comprise a cell group index for said secondary cell, assigning said secondary cell to one of said at least one secondary cell group identified by said cell group index; and (b) otherwise, assigning said secondary cell to said primary cell group; ii) transmit a random access preamble on random access resources of a secondary cell in said secondary cell group in response to receiving a control command from said base station; and iii) receive a random access response on said primary cell, said random access response comprising a timing advance command for said secondary cell group.

16. The wireless device of claim 15 , wherein said at least one control message configured to further cause in said wireless device configuration of a time alignment timer for each of said plurality of cell groups, said time alignment timer starting or restarting in response to said wireless device receiving a timing advance command to adjust uplink transmission timing of a commanded cell group in said plurality of cell groups.

17. The wireless device of claim 15 , wherein said plurality of dedicated parameters further comprise a time alignment timer parameter for each cell group in said plurality of cell groups.

18. The wireless device of claim 15 , wherein said plurality of dedicated parameters: a) are specific to said wireless device in a plurality of wireless devices; b) comprise a first dedicated parameter applicable to all activated secondary cells in at least one secondary cell; and c) comprise a second dedicated parameter, being secondary cell specific, and being applicable to only one secondary cell in said at least one secondary cell.

19. The wireless device of claim 15 , wherein said instructions further cause said wireless device to receive a timing advance command from said base station, said timing advance command configured to cause substantial alignment of reception timing of uplink signals in frames and subframes of a cell group at said base station, said timing advance command comprising an index identifying said cell group.